Fill a 15-inch wide wok with two-inch deep boiling water. You will also need cover for wok, and one medium-sized stainless steel bowl, to put fish in, when you cook it on top of the boiling water.

Season the fish with salt, pepper and calamansi juice.

For the white sauce:

Melt the butter in a small saucepan. Add the all-purpose flour. Mix with a wire whisk. Add the fresh milk and cook until creamy. Turn off fire, and season with salt and pepper.

To cook the fish:

Put the spinach or kangkong leaves in the bowl. Top with onions, mushrooms slices, and seasoned fish. Put the bowl on top of the boiling water. Cover and cook for 15 minutes. Check the fish with a fork for doneness. With two turners (sianse), transfer fish and vegetables on to a serving platter. Top with the white sauce.

Garnish with 1/2 cup chopped spring onions or capers. (Capers are sold in bottles in supermarkets at the olive section). Serves four to six.